In general, magnetic resonance imaging (MRI) examinations are based on the interactions among a primary magnetic field, a radiofrequency (RF) magnetic field, and time varying magnetic gradient fields with gyromagnetic material having nuclear spins within a subject of interest, such as a patient. Certain gyromagnetic materials, such as hydrogen nuclei in water molecules, have characteristic behaviors in response to external magnetic fields. The precession of spins of these nuclei can be influenced by manipulation of the fields to produce RF signals that can be detected, processed, and used to reconstruct a useful image.
During imaging sequences, the time varying gradient fields are generated by application of current to a series of gradient coils. Additionally, RF fields are generated simultaneously with the gradient fields by application of current to RF coils. RF shielding on the outside of the RF coils may help reduce direct interaction between the gradient coils and the RF coils as well as shield external components and/or the environment from electromagnetic interference. However, the positioning of the RF coils and/or shielding may cause issues concerning efficiency as well as patient comfort.